%0 Journal Article %T Spatial spreading of magnetospherically reflected chorus elemDisecunsstiosnsinthe inner magnetosphere %+ Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E) %+ Plasma Theory Department %+ Department of Astronomy and Space Physics [Kyiv] %+ Space Research Institute of the Russian Academy of Sciences (IKI) %+ Centre National d'Études Spatiales [Toulouse] (CNES) %A Breuillard, Hugo %A Zaliznyak, Y %A Agapitov, O. V. %A Artemyev, A.V. %A Krasnoselskikh, V. %A Rolland, G. %< avec comité de lecture %@ 0992-7689 %J Annales Geophysicae %I European Geosciences Union %V 31 %P 1429–1435 %8 2013 %D 2013 %R 10.5194/angeo-31-1429-2013 %K Radio science %Z Sciences of the Universe [physics]Journal articles %X Chorus-type whistler waves are known to be generatedin the vicinity of the magnetic equator, in the lowdensityplasma trough region. These wave packets propagatetowards the magnetic poles, deviating from the magneticfield lines, before being eventually reflected at higher latitudes.Magnetospheric reflection of whistler waves results inbounce oscillations of these waves through the equator. Ourstudy is devoted to the problem of geometrical spreading ofthese whistler-mode waves after their first magnetosphericreflection, which is crucial to determine where wave–particleinteractions occur. Recently, experimental studies stated thatthe relative intensity of the reflected signal was generally between0.005 and 0.05 of the source signal. We model suchwave packets by means of ray tracing technique, using awarm plasma dispersion function along their trajectory anda realistic model of the inner magnetosphere. We reproducethe topology of the reflected energy distribution in the equatorialplane by modeling discrete chorus elements generatedat the equator. Our calculations show that the spatial spreadingis large and strongly dependent upon initial wave parameters,especially the chorus wave frequency. Thus, the divergenceof each element ray trajectories can result in the fillingof a large region (about 4 Earth radii around the source) ofthe magnetosphere and a reflected intensity of 0.005–0.06 ofthe source signal in the equatorial plane. These results are ingood agreement with previous Cluster and THEMIS observations. %G English %2 https://insu.hal.science/insu-01175235/document %2 https://insu.hal.science/insu-01175235/file/angeo-31-1429-2013.pdf %L insu-01175235 %U https://insu.hal.science/insu-01175235 %~ OBSPM %~ INSU %~ CNRS %~ UNIV-ORLEANS %~ CNES %~ OSUC %~ LPC2E %~ PSL %~ OBSPM-PSL